var plane = {
    fire: function(){
      console.log( '发射普通子弹' );
    }
}

var missileDecorator = function(){
    console.log( '发射导弹' );
}

var atomDecorator = function(){
    console.log( '发射原子弹' );
}

var fire1 = plane.fire;

plane.fire = function(){
    fire1();
    missileDecorator();
}

var fire2 = plane.fire;

plane.fire = function(){
    fire2();
    atomDecorator();
}

plane.fire();
// 分别输出：发射普通子弹、发射导弹、发射原子弹